1. Field of the Invention
The invention relates to ion traps and systems and methods that use ion traps.
2. Discussion of the Related Art
FIG. 1A illustrates a conventional design for a planar ion trap 8. The ion trap 8 includes central electrode 10, inner surrounding electrodes 12, and outer surrounding electrodes 14. The electrodes 10, 12, 14 have rectangular shapes, and the outer electrodes 14 are segmented. The electrodes 10, 12, 14 are flat metal layers that are located on a planar top surface of a quartz or alumina substrate 16. Thus, the electrodes 10, 12, 14 of the ion trap 8 have a planar structure.
Operating the planar ion trap 8 involves applying a high frequency voltage between the inner surrounding electrodes 12 and the central and outer surrounding electrodes 10, 14, and applying a static or quasi-static voltage between the segments of outer surrounding electrodes 14. The high-frequency voltage produces a pattern of electric fields, E, with a small quadruple component in a cylindrical free-space region 18 that is located above and between the paired inner surrounding electrodes 12 as illustrated is FIG. 1B. In the free-space region 18, the high-frequency electric fields can traps ions vertically and laterally. The static or quasi-static voltage produces an electric field pattern that can trap the ions along the axis of the ion trap 8. Thus, the combination of high frequency and static or quasi-static voltages traps ions in the planar ion trap 8.
The ion trap 8 also includes a number of metallic electrical leads (not shown) that run along the top surface of the substrate 16. The electrical leads connect the electrodes 10, 12, 14 to high-frequency and static or quasi-static voltage drivers (not shown). These drivers are located off the edges of the substrate 16.